DESCRIPTION: This proposal uses behavioral testing and functional neuroimaging to examine rapid automatized naming (RAN) in adult dyslexics. Although the RAN is widely used in the study of dyslexia, the cognitive processing sub-components of rapid naming are not well understood. The present project examines three cognitive aspects of rapid naming-phonological, lexical/semantic and automatized processing-and uses functional magnetic resonance imaging (fMRI) to elucidate the neural systems involved in these component processes. Two aspects of phonological processing are assessed translation of visually presented letters and digits into spoken output and phonological priming during naming. If poor rapid naming is due to impaired phonological processing, then brain activation patterns associated with these phonological tasks are predicted to be different in dyslexics and normals. However, RAN impairment may also reflect problems with lexical retrieval. This possibility is tested by comparing a difficult naming task to a less difficult naming task. In the difficult condition, pictures of animals that are similar in shape are named, whereas in the less difficult condition, pictures of animals with disparate shapes are named. The difficult task taxes the naming system at levels prior to phonological processing by making greater demands on perceptual analysis and lexical/semantic retrieval. Functional neuroimaging will determine whether brain activation patterns of dyslexics are different from those of normal controls with a difficult rapid naming task. If so, then RAN difficulties may not restricted to phonological problems. RAN impairment may also reflect problems with the automaticity of phonological decoding. In dyslexic readers, the conversion from visually presented letters or words to sounds is not as automatic as it is in normal readers. This impairment may be specific to verbal materials or it may reflect a more general learning problem. The present study uses implicit temporal sequence learning in the context of rapid naming to assess whether dyslexics are impaired in implicit learning, or whether their RAN deficit can be explained by a specific problem with automatizing verbal material. The findings from this study can potentially be used for tailoring dyslexic treatment programs, many of which currently emphasize development and tuning of phonological skills. Neuroimaging findings will help understand the functional organizational of neural systems involved in impaired and normal naming.